[PATCH] enabling LKM for custom beeper

[PATCH] enabling LKM for custom beeper

[Christian W. Zuckschwerdt]

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Hi Linus, Alan,

this patch has proven to be stable an useable. It hasn't changed 
since 2.2.13.

The patch affects kd_mksound and kd_nosound which are responsible for
generating sound.
The default behaviour won't be changed but it's now possible for a LKM to
hook into these calls and change the way the system bell rings.

Changes in struct timer_list made a separate patch for 2.4.0 necessary.

Please incorporante into next release of 2.{2,4} if appropriate; TIA,

  cu.
    :
    Christian

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--- drivers/char/vt.c.orig	Mon Aug  9 21:04:39 1999
+++ drivers/char/vt.c	Sun Jan 23 17:10:28 2000
@@ -92,18 +92,20 @@
     || (defined(__mips__) && !defined(CONFIG_SGI))
 
 static void
-kd_nosound(unsigned long ignored)
+_kd_nosound(unsigned long ignored)
 {
 	/* disable counter 2 */
 	outb(inb_p(0x61)&0xFC, 0x61);
 	return;
 }
 
-void
+void (*kd_nosound)(unsigned long ignored) = _kd_nosound;
+
+static void
 _kd_mksound(unsigned int hz, unsigned int ticks)
 {
 	static struct timer_list sound_timer = { NULL, NULL, 0, 0,
-						 kd_nosound };
+						 _kd_nosound };
 
 	unsigned int count = 0;
 
--- kernel/ksyms.c.orig	Wed Oct 20 02:14:02 1999
+++ kernel/ksyms.c	Sun Jan 23 17:10:28 2000
@@ -62,6 +62,9 @@
 extern void free_dma(unsigned int dmanr);
 extern spinlock_t dma_spin_lock;
 
+extern void (*kd_nosound)(unsigned long ignored);
+extern void (*kd_mksound)(unsigned int count, unsigned int ticks);
+
 #ifdef CONFIG_MODVERSIONS
 const struct module_symbol __export_Using_Versions
 __attribute__((section("__ksymtab"))) = {
@@ -341,6 +344,8 @@
 EXPORT_SYMBOL(register_reboot_notifier);
 EXPORT_SYMBOL(unregister_reboot_notifier);
 EXPORT_SYMBOL(_ctype);
+EXPORT_SYMBOL(kd_nosound);
+EXPORT_SYMBOL(kd_mksound);
 EXPORT_SYMBOL(secure_tcp_sequence_number);
 EXPORT_SYMBOL(get_random_bytes);
 EXPORT_SYMBOL(securebits);
--- include/linux/vt_kern.h.orig	Fri Oct 22 01:48:41 1999
+++ include/linux/vt_kern.h	Sun Jan 23 17:10:28 2000
@@ -30,7 +30,7 @@
 	struct wait_queue *paste_wait;
 } *vt_cons[MAX_NR_CONSOLES];
 
-void (*kd_mksound)(unsigned int hz, unsigned int ticks);
+extern void (*kd_mksound)(unsigned int hz, unsigned int ticks);
 
 /* console.c */
 

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--- linux-2.4.0-pristine/drivers/char/vt.c	Thu Jan  4 22:00:55 2001
+++ linux-2.4.0/drivers/char/vt.c	Sun Jan 28 21:01:37 2001
@@ -98,17 +98,19 @@
     || (defined(__arm__) && defined(CONFIG_HOST_FOOTBRIDGE))
 
 static void
-kd_nosound(unsigned long ignored)
+_kd_nosound(unsigned long ignored)
 {
 	/* disable counter 2 */
 	outb(inb_p(0x61)&0xFC, 0x61);
 	return;
 }
 
-void
+void (*kd_nosound)(unsigned long ignored) = _kd_nosound;
+
+static void
 _kd_mksound(unsigned int hz, unsigned int ticks)
 {
-	static struct timer_list sound_timer = { function: kd_nosound };
+	static struct timer_list sound_timer = { function: _kd_nosound };
 	unsigned int count = 0;
 	unsigned long flags;
 
--- linux-2.4.0-pristine/include/linux/vt_kern.h	Thu Jan  4 23:51:24 2001
+++ linux-2.4.0/include/linux/vt_kern.h	Sun Jan 28 21:00:32 2001
@@ -30,7 +30,7 @@
 	wait_queue_head_t paste_wait;
 } *vt_cons[MAX_NR_CONSOLES];
 
-void (*kd_mksound)(unsigned int hz, unsigned int ticks);
+extern void (*kd_mksound)(unsigned int hz, unsigned int ticks);
 
 /* console.c */
 
--- linux-2.4.0-pristine/kernel/ksyms.c	Wed Jan  3 01:45:37 2001
+++ linux-2.4.0/kernel/ksyms.c	Sun Jan 28 21:00:32 2001
@@ -62,6 +62,9 @@
 extern void free_dma(unsigned int dmanr);
 extern spinlock_t dma_spin_lock;
 
+extern void (*kd_nosound)(unsigned long ignored);
+extern void (*kd_mksound)(unsigned int count, unsigned int ticks);
+
 #ifdef CONFIG_MODVERSIONS
 const struct module_symbol __export_Using_Versions
 __attribute__((section("__ksymtab"))) = {
@@ -455,6 +458,8 @@
 EXPORT_SYMBOL(machine_halt);
 EXPORT_SYMBOL(machine_power_off);
 EXPORT_SYMBOL(_ctype);
+EXPORT_SYMBOL(kd_nosound);
+EXPORT_SYMBOL(kd_mksound);
 EXPORT_SYMBOL(secure_tcp_sequence_number);
 EXPORT_SYMBOL(get_random_bytes);
 EXPORT_SYMBOL(securebits);